product_list = [
    ('p30',3000),
    ('mac pro',16000),
    ('milk tea',30),
    ('bike',800),
    ('crabs',80),
    ('head first python',128),
    ('book',88),
    ('watch',80000)
]
shopping_car = []
zhifubao = input('请输入你的支付宝数字余额：')
if zhifubao.isdigit():
    zhifubao = int(zhifubao)
    while True:
        for i in product_list:
            print(product_list.index(i),i)
        choice = input("请输入商品编号：")
        if choice.isdigit():
            choice = int(choice)
            if choice >=0 and choice<=7:
                if zhifubao >= product_list[choice][1]:
                    zhifubao = zhifubao - product_list[choice][1]
                    shopping_car.append(product_list[choice])
                    print('你已经将商品%s添加到了购物车，你的支付宝余额是%s'%(product_list[choice][0],zhifubao))
                else:
                    print('你的支付宝余额不足，请选择其他商品')
            else:
                print('你选择的商品不在商品列表里面')
        elif choice == 'q':
            print('购物车清单')
            for i in shopping_car:
                print(i)
            print('你的支付宝余额是%s'%zhifubao)
            break
        else:
            print('请输入商品编号：')
else:
    print('请输入支付宝余额')